Internal-combustion engine



NOV. 3, 1931. R sKlNNER I 1,830,136

INTERNAL COMBUSTION ENGINE F 1929 3 Sheets-Sheet l Nov. 3, 1931. R. SKINNER 5 J INTERNAL COMBUSTION ENGINE Filed July 10. 1929 s Sheets-Sheet 2 NOV. 3, 1931. I R 1 NE 1,830,136

INTERNAL COMBUSTION ENGINE Filed July 10, 1929 5 Sheets-Sheet s Pstented Nov, 3, 1931 PATENT OFFM'IE RALPH L. SKINNER, F DETROIT, MICHIGAN INTERNAL-COMBUSTION ENGINE Application filed July 10, 1929. Serial No. 377,260.

My invention concerns certain structural and functional features of novelty and advantage in internal-combustion engines, more y particularly those of the sliding valve type, as distinguished from the poppet-valve style, whereby to more efiectively. seal the cylinders and their associated mechanical elements against loss of compression or leakage of gas pressure, to secure more efficient scavenging of the cylinders of the exhaust or exploded gases with resulting diminution of dilution of the new charges of fuel mixtures, to so shape, arrange and combine the mechanical parts to avoid detrimental operating results due to the heating, expansion, etc., to 'make the valves and their actuating devices of such formand manner of action as to produce improved performance of the engine as a whole, and to obtain other objects and purposes which will be understood from a consideration of several embodiments of the invention illustrated in detail in the accompanying drawings, forming a part of this specification, and throughout the several views of have been used to designate the same parts throughout the viewsl In these drawings:

Figure 1 is a nearly central, longitudinal, vertical cross-section on line 11 of Figure 3 through a portion of one cylinder of a multicylinder internal-combustion engine incorporating the features of the present invention;

Figure 2 is an enlarged part only of Figure 1;

Figure 3 1s a horizontal section on line 3-3 of Figure 1;

Figure 4 is a horizontal section on line 4-4 of Figure 1;

Figure 5 is a similar section on line 5-5 of Figure 1; and

Figures 6, 7:,and 8 are fragmentary sections showing slightly modified constructions of the sealing-reed.

Referring to these drawings, it will be seen that the engine includes a water-jacketed, outer cylinder 22 having a single or uninterrupted fuel-inlet port 23 and an opposite,

continuous or single, unbridged, wider exhaust-port 24, the top of the cylinder being which like reference numerals, for simplicity,-

closed by a demountable, depressed head 25 accommodating the usual spark-plug 26, such head being covered by a housing or casing 27 'rovidin a water-'acket or coolin s ace or sleeve 31 is provided being sustained or held in place solelyfrom its lower end by screws 32, 32 engaging threaded holes in supporting means or lugs 33 depending from the cylinder-casting 21 into the crank-case, and, within such inner cylinder, a piston 34 rea ciprocates being connected in the usual manner to the crank-shaft 29 by a connecting-rod 35.

A comparatively-narrow, longitudinallysplit, expansible and contractible sealingring 36 bears on the plane or'flat, upper end of such inner cylinder and has a bridged or divided inlet-port 37 therethrough in substantial register with, and of practically the same size as, said cylinder inlet-port 23, and a single, unbridged or unstrutted, continuous exhaust-port 38 of practically the same dimensions as the exhaust-port 24 of the outer cylinder, such sealing-ring exhaust-port being therefore wider than its-inlet-port.

The over-lapped joint 39 of the split in the sealing-ring is located in the central bridge or strut of its inta ke-port, all as is clearly shown in Figure 3.

A semi-circular, ported, inlet-valve 41, having a bridged intake-port 42 of approximately the same dimensions as the admissionports of the outer cylinder and sealing-ring, 23 and 37 respectively, and a companion, semi-circular, ported exhaust-valve 43, having an unobstructed or unbridged dischargeport 44 of practically the same length and width as the delivery-ports 24 and 38 of the cylinder and sealing-ring,,and hence wider than the intake-port 42, are located between,

and are slidable lengthwise of, the outer cylinder on the outside and the inner cylinder 31, sealing-ring 36 and cylinder-head 25 onthe inside.

Inlet-valve 41 is reciprocated in proper timed relation to the operation of the other parts of the mechanism by a connecting-rod 45 hinged at 46 to a lug 47 on the lower end of the valve, the other end of the rod being rockingly mounted on an eccentric or crank pin 48 of a horizontal, valve-operating shaft 49 disposed lengthwise the group of enginecylinders and revoluble in suitable bearings of. which only one 51 is shown, such inletvalve shaft being rotated from the main, engine crank-shaft by any suitable mechanism, not deemed necessary to show.

In similar manner, the exhaust-valve 43 is reciprocated by a comparable connecting-rod 52 actuated by a crank or eccentric pin 53 of a properly mounted and rotated shaft 54 on the side of the cylinders opposite the location of the inlet-valve shaft 49, the throw or eccentricity of the pin 53 being greater than that of pin 48, whereby the stroke of the exhaust-valve is longer and more rapid than that of the inlet-valve, the two shafts being rotated at the same speed.

It is to be noted, that, in both instances, the path of vertical travel of the axis of the pivotal connection of the connecting-rod with the valve is offset inwardly of the axis of the corresponding shaft 49 or 54 and that the two shafts rotate at the same speed in the same direction and not in opposite directions, for a reason hereinafter stated.

The piston and valves are lubricated in any approved manner, as by the well-known splash system by means of the oil in the cranle case thrown up by the revolving cranks, and, to facilitate the distribution of the oil ovel the surfaces of the cylinders, valves and cylinder-head, the valves are provided on their outer faces at 55 with any appropriate arrangement of oil channels, the outer surface of the inner cylinder having oil grooves '56 and the surface of the head having similar channels 57;

To aid or assist the entrance of oil between the surfaces of the inner cylinder and the valves, the former is provided with a row of holes 58 therethrough in such a position that, at the end of the down stroke of the piston, the oil wiped off of the inner cylinder by the piston-rings will naturally flow more or less through these apertures to the inner surfaces of the valves.

In order to maintain the sealing-ring at all times in proper engagement or bearing relation with the end surface of the inner cylinder with which it is in contact, and to assist in keeping the sealing-ring joint from leaking, an endless hold-down ring 59 is provided just above, and bearing directly on, the top, fiat, end face of the sealing-ring, such member 59 being relatively thin and having a bottom, marginal, inwardly-projecting ledge, flange, or lip 61 on which the gaseous pressure in the cylinders act, tendin to press the ring as a whole down on the sea ing-ring.

Above such internal, bottom ledge, the hold-down ring is slidingly, yet movably, accommodated between the two semi-circular valves and an outstanding, circular rib 62 on a lower, reduced-diameter part 63 of the cylinder-head 25.

Gas pressure in substantial amount is not always present in the cylinders to force the hold-down ring sufliciently firmly on the sealing-ring, especially during the upward travel of one or both valves, and, accordingly, supplemental, mechanical means are employed to cooperate with the action of the ring ledge.

To this end, a divided or sectional ring 64.

having a plurality of round cavities 65 in its upper surface, is located above and overlies the top end of the hold-down ring 59, being located between a shoulder 66 on the cylinderhead and the rib 62 thereof.

Each pocket 65 houses a short, coiled spring 67 bearing at its upper end against the cylinder-head surface or shoulder 66 and at its lower end against the bottom Wall of its cavity, whereby such springs unitedly and conjointly tend to press the hold-down ring on to the sealing-ring and the latter on to the end of the inner cylinder.

Inasmuch as the more or less open, unstrutted or unbridged exhaust-port portion of the sealing-ring is incapable of withstanding as much downward pressure thereon as the other parts of the ring without collapsing, and, since such exhaust-port section of the ring requires such a force acting thereon l to hold the sealing-ring in place without ris ing from its seat on the inner cylinder during the upward travel of the exhaust-valve on which it bears, an excess pressure is exerted by the springs on the other parts of the ring, thus keeping the latter, as a whole, against improper shifting or undesired movement.

Wherefore, a greater number of the springs 67, twice as many in the present instance, are

used over the intake-port and adjacent portions of the sealing-ring than are employed over the exhaust-port part thereof, thus in a measure compensating for the absence of a full complement over the exhaust-port section.

It is desirable to prevent leakage or the escape of gas pressure from the cylinders up past the hold-down ring, and, of course, it is also of advantage to preclude the hot combustion or cylinder gases from reaching these little springs.

For the accomplishment of this, an endless. circular sealing-reed 68 is fitted tightly over the lesser-diameter section 63 of the cylinderhead and it bears against the under face of the circular-rib 62, thus assuring that no gas can escape between the reed and head, the former also having a thin, outwardly-flaring, depending, flexible or elastic flange 69 pressing firmly against the inner face of the holddown ring 59.

The normal external diameter of the flange 69 is slightly greater than the internal calibre of the hold-down ring so that when they are assembled in the manner shown there is an actual metal to metal contact between the reed lip and the confining hold-down ring.

The natural tendency of expansion of such lip or flange and the gas pressure in the cylinder which has free access thereto, promoting its expansion or outer fiexure into sealing engagement with the hold-down ring, assures prevention of leakage of pressure between them.

To assist in sealing, closing or covering the joint between the sealing-ring and the inner cylinder, a thin, flexible, metal gland 71 may be employed to overlap the two, contacting members involved, such element being held in place by means of its outstanding flange 72 occupying and snugly fitting in a circular groove in the inner face of the sealing-ring. In similar manner, the joint between the sealing and hold-down rings may be protected by a second, like gland 73.

In both instances, the gas pressure in the cylinders expands the glands, slightly and presses them firmly against the elements which they overlie or overlap, thus efiectively sealing or closing the joints between the members.

As a further means of insuring the maintenance 'of pressure and compression tight relations between the sealing-ring and the inner cylinder, the hold-down ring, and the valves, the sealing-ring is provided in its face in engagement with the end of the inner cylinder with an oil groove 74, in its surface in contact with the hold-down ring with a similar lubricant groove -75, and in its outer, curved surface bearing on the sliding valves with similar grooves, 76, 76 located above and below the ports of the ring.

In such instance, the ends of the groove or Lhannel terminate slightly short of, and do not intersect, the sealing-ring oint.

\ Oil collects in these various channels, and, by so doing, it acts to seal the associated joints between the contacting surfaces, such sealing or closing action being increased or augmented by the gradual deposit and accumulation of carbon on the surface of the member which the groove faces and covers.

It is immaterial in which of the two members bearing on one another-the groove or channel is present, for example, it could just as well be in the end surface of the inner cylinder as in the associated sealing-ring.

The refrigerating or cooling effect of the incoming, gaseous, fuel mixture on the divided, sealing-ring, inlet-port strut or bridge prevents the development of a temperature 7 high enough to be conducive to the formation of carbon, which. if it occurred in substantial measure to fill the gap in the ring joint, would not permit proper expansion and contraction of the ring, especially under high speed operating conditions, with probable resultant seizure.

By placing the gap or joint in such intakeport strut there is only a soft carbon formation causing no damage and not preventing ring growth.

From the foregoing, it will be apparent that the sealing-ring, by reason of its inherent inclination to enlarge, supplemented by the gas pressure in the cylinders acting on it and tending to expand ;;it, is forced outwardly against the two valves, pressing them firmly against the inner surface of the outer cylinder and maintaining a gas pressure tight relation therewith.

The sealing-ring expands and contracts in minor degree under varying heat and cold conditions and the construction is such as to render this possible and at the same time prevent blow-by through the various joints.

The sealing-ring during the performance of its important functions is held down to its work by the hold-down ring which in turn is forced downwardly by the variable gas pressure itself acting on its ledge and by the plurality of short springs.

Escape of gas under pressure between the hold-down ring and the cylinder-head is avoided by the gas-pressure enlarged sealingreed.

As has been indicated, none of the parts of the exhaust-ports are strutted or bridged, and, consequently. a free and unobstructed passage of the hot, exhaust gases occurs with the result that the cylinder is more thoroughly and completely scavenged or freed of exploded gases than has heretofore been usual with resultant less dilution of the next, succeeding, gaseous, fuel-mixture charge, hence producing greater power in the engine and obtaining a substantially improved economy in fuel consumption Such eflicient, prompt and more complete discharge of the hot gases of combustion reduces the heating effect of such gases in the engineandlessens the destructive action of the gases on the margins or edges of the exhaust-ports in the cylinder, valves and seal-' ing-ring.

The absence of any obstructing strut or 7 likely to allow leakage of the gases under pressure.

For example, if such a barrier or bridge .be employed in the exhaust-port of the sealing-ring, it causes that particular part of the ring to expand up and down more than the other portions of the ring, and hence such distorted shape of the ring renders it difficult, it not impossible, to keep the joints between it and the inner cylinder and the hold-down ring properly sealed.

Such detrimental warping or deformationis all the more likely to occur when such a bridge is used, because it is always in the direct path of the hot discharging gases, whereas the other parts of the ring are in contact with the valves which assists in conducting the heat away from them, hence keepin them cooler than the highly heated bridge.

The absence of strut in the port of the exhaust-valve eliminates or avoids heat distortion which tends to result in an improper seal between the inner surface of the valve and the outer face of the sealing-ring.

The omission of exhaust-port struts excludes unnecessary beat-accumulating means and the whole performance of the engine is cooler by reason of the absence of the heat absorbing bridge and this allows the maintenance of a better oil film on the ring and valve.

In this connection, it should be borne in mind, that, even with no strut in the exhaustport of the sealing-ring, the latter cannot expand so as to catch on the edges of the valveport, because the upper part of the sealingring is always above the valve-port and hence prevents undue enlargement of the sealingring as a whole, including that part which cooperates with the valve-port.

Turning now to a consideration of the valve-operating mechanisms, it will be observed from what precedes, that the stroke of the exhaust-valve with its wider port is longer than that of the inlet-valve with its narrower port.

The valve opening area increases more in proportion than the increase in the length of valve stroke.

The advantage of a short alve stroke, as in the case of the inlet-valve, is the low valve inertia, whereas the benefit of the long stroke is the larger port opening area with more rapid opening.

Thus the, one advantage is present in the exhaust-valve and the other in the inlet-valve.

If the point of attachment of the connecting-rod with the valve were exactly above the center or axis of the eccentric or crank-shaft operating the valve, the curve representing the opening and closing of the valve would be symmetrical, but by offsetting these two points, the curve has a relatively steep angle on one side and a comparatively flat angle on the other side, and the directions of rotation on the hold-down ling,

of the two eccentric shafts are so chosen, as illustrated, to take advantage of this irregular or immethodical curve to advantageously cause the intake-valve to open faster than it closes and the exhaust-valve to close faster than it opens.

It is desirable to have the intake-valve open fully either before, or exactly at the time of, maximum downward piston velocity, and, if the complete opening of the valve is subsequent to such greatest piston speed, an objectionable wire-drawing effect on the gases through the port occurs, causing a harmful retardation of fuel flow into the cylinder.

Such an occurrence at slow engine speeds is not important, but at its higher speeds, it is particularly objectionable, materially reducing the power which the engine is capable of developing.

By reason of the early full opening of the intakevalve above specified, the gaseous fuel is permitted to flow into the cylinder under unusually favorable conditions for the production of power at higher speeds, particularly as compared with the action of the usual Knight engine.

It is desirable to have the opening of the valves conform more or less closely to the piston velocities and with this construction the intake-vz'xlve opens quickly which coincides with the rapid downward movement of the piston during the first half of the induction stroke, the exhaustvalve opening slowly which corresponds to the gradual travel of the piston during the first half of the exhaust stroke.

The exhaust-valve is favorably operated to retain the working pressure in the cylinder as long as possible with a certain breadth of timing and still have a completely or adequately scavenged cylinder at the top of the piston stroke.

Such result is obtained easily by the oil'- setting specified to secure a slow opening but quick closing of the exhaust-port.

Other forms of sealing-reeds are depicted in Figures 6 to 8 inclusive and in the structure of Figure 6, a reed cage 81 fitted tight on the cylinder-head holds a number of superposed, circular, flexible reeds 82, 82 bearing in that of Figure 7 a single, flexible, metal ring 83 of inverted U-shape is employed, whereas in the appliance of Figure 8, a cage 84 and associated saaeing-rings 85 hold together a number of separated, elastic reeds 86, 86.

These modified structures operate in much the same way as the preferred construction and seemingly require no further description.

In all of the various forms of sealing-reeds specified, it is desirable, in order to obtain maximum functioning efliciency of the engine, to have the cylinder-head, the sealingreed and the hold-down ring made of metals of substantially the same coefficient of heat rea ies expansion and contraction, so that under all circumstances the sealing-reed will maintain proper gas pressure tight relation with the hold-down ring without danger of excessive outward pressure of the reed which might prlevent the springs 67 from operating proper y.

The inventionis in no way confined to the especial embodiments set forth and many changes may be incorporated in the structures without abandonment of any of the substan tial advantages accruing from the use of the invention, as defined by the appended claims.

I claim:

1. Inan internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, a second cylinder inside of and spaced inwardly away from said outer cylinder, a sealingring bearing endwise on said inner cylinder and having ports in substantial register with said outer cylinder ports, arcuate valves slidable between said outer cylinder and said inner cylinder and sealing-ring to control said ports, means to reciprocate said valves, a piston reciprocatory in said cylinder, a holddown ring bearing on the top of said sealingring, and a sealing-reed between said cylinder-head and said hold-down ring having a flexible portion engaging the' inner surfaceof said hold-down ring subjected to the gas pressure in said cylinders which forces such portion against said hold-down ring tending to maintain a gas pressure tight sea between them. I

2. In an internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, a second cylinder inside of and, spaced inwardly away from said outer cylinder, a sealingring bearing endwise on said inner cylinder and having ports in substantial register with said outer cylinder ports, arcuate valves slidable between said outer cylinder and said inner cylinder and sealing-ring to control said ports, means to reciprocate said valves, a piston reciprocatory in said cylinder, a holddown ring bearing on the top of said sealingring, and a sealing-reed-between said cylinder-head and said hold-down ring having an outwardly-flarin flexible flange engaging the inner surface 0 said hold-down ring subjected to the gas pressure in said cylinders which forces such flange against said holddown ring tending to maintain a gas pressure tight seal between them.

3. In an internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, a

second cylinder inside of and spaced inwardly cylinder ports, arcuate valves slidable beaway from said outer-cylinder, a longitudinally-split expansible. sealing-ring bearing endwise on said inner cylinder and having ports in substantial register with said outer tween said outer cylinder and said inner cylinder and sealing-ring to control said ports, means to reciprocate said valves, a piston reciprocatory in said cylinder, an endless holddown ring bearing endwise on thatop of said sealing-ring, and an endless sealing-reed between said cylinder-head and said hold-down ring having a flexible portion engaging the inner surface of said hold-down ring subjected to the gas pressure in said cylinders which forces such portion against said holddown ring tending to maintain a gas pressure tight seal between them.

4. In an internal-combustion engine, the combination of an outer cylinder having in: let and exhaust ports, a head for said cylinder,'a second cylinder inside of and spaced inwardly longitu inally-split expansible sealing-ring bearing endwise on said inner cylinder and having ports in substantial register with said outer cylinder ports, arcuate valves slidable between said outer cylinder and said inner cylinder and sealing-ring to control said ports, means to reciprocate said valves, a piston reciprocatory in said cylinder, an endless hold-down ring bearing endwise on the top of said sealing-ring, resilient means tending to force said hold-down ring towards said sealing-ring, and an endless sealing-reed between said cylinder-head and said holddown ring having a flexibleportion engaging the inner surface of said hold-down ring subjected to the gas pressure in said cylinders which forces such portion against said hold-down ring tending to maintain a gas pressure tight seal between them, said sealing-reed being located to prevent the gas pressure in said cylinders from reaching said resilient means. i

5.- In an internal-combustion engine, the combination of cylindermeans having inlet and exhaust ports, a head for said cylindermeans, asealing-ring bearing endwise on sald cylinder means and having ports in substantial' register with said inlet and exhaust ports, valves controlling said ports slidable between said cylinder-means and said sealing-ring, means to reciprocate said valves, a hold-down ring bearing endwise on the top away from said outer cylinder, a k

of said sealing-ring, and a sealing-reed besealing-ring bearing endwise on said inner cylinder and having a single exhaust portin iii.

substantial register with the exhaust port of said outer cylinder and a bridged inlet-port in substantial register with the inlet-port of said outer cylinder with said bridge arranged longitudinally of the sealing-ring, valves controlling said cylinder and sealing-ring ports slidable between said outer cylinder and said inner cylinder and sealing-ring, means to reciprocate said valves, and means acting on the upper end of said sealing-ring tending to press it down against said inner cylinder with greater force on the bridged inlet-port portion of the sealing-ring than on the unbridged exhaust-port part thereof.

7. In an internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, a second cylinder inside of and spaced inwardly away from said outer cylinder, a sealing-ring bearing endwise on said inner cylinder and having a single exhaust-port in substantial register with the exhaust-port of said outer cylinder and a bridged inlet-port in substantial register with the inlet-port of said outer cylinder with said bridge arranged longitudinally of the sealing-ring, valves controlling said cylinder and sealing-ring ports slidable between said outer cylinder and said inner cylinder and sealing-ring, means to reciprocate said valves, a hold-down ring bearing endwise on said sealing-ring, and means acting on the upper end of said hold-down ring tending to press it down against said sealing-ring with greater force on the bridged inlet-port portion of the sealing-ring than on the unbridged exhaust-port part thereof.

8. In an internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, a second cylinder inside of and spaced inwardly away from said outer cylinder, a sealing-ring bearing endwise on said inner cylinder and having a single exhaust-port in substantial register with the exhaust-port of said outer cylinder and a bridged inlet-port in substantial register with the inlet-port of said outer cylinder with said bridge arranged longitudinally of the sealing-ring, valves controlling said cylinder and sealing-ring ports slidable between said outer cylinder and said inner cylinder and sealing-ring, means to reciprocate said valves, a hold-down ring hearing endwise on said sealing-ring, and a plurality of springs pressing said hold-down ring towards said sealing-ring with greater force on the bridged inlet-port portion of the sealing-ring than on the unbridged exhaust-port part thereof.

9. In an internal-combustion engine. the combination of cylinder-means having inlet and exhaust ports, a head for said cylindermeans, a sealing-ring bearing endwise on said cylinder-means and having a single GX- haust-port in substantial register with the aeaeaae exhaust-port of said cylinder-means and a bridged inlet-port in substantial register with the inlet-port of said cylinder-means with said bridge arranged longitudinally of the sealing-ring, valves controlling said ports slidable between said cylinder-means and said sealing-ring, means to reciprocate said valves, and means acting on said sealing-ring to press it against said cylinder-means with greater force on the bridged inlet-port por tion of the sealing-ring than on the unbridged exhaust-port part thereof.

10. In an internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder. a second cylinder inside of and spaced inwardly away from said outer cylinder, a sealing-ring bearing endwise on said inner cyl inder and having ports in substantial register with said cylinder ports, a piston reciprocatory in said inner cylinder, arcuate 'alves controlling said ports slidable between said outer cylinder and said. inner cylinder and sealing-ring, means to reciprocate said valves, means to hold said sealingring to its bearing on said inner cylinder. and means to lubricate said valves and piston, one at least of the contacting surfaces of said sealing-ring and inner cylinder having a channel lubricant in which tends to seal the joint between the surfaces against the escape of gas under pressure.

11. In an internal-combustion engine. the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder. a second cylinder inside of and spaced inwardly away from said outer cylinder, a sealing-ring bearing endwise on said inner cylinder and having ports in substantial register with said cylinder ports. a piston reciprocatory in said inner cylinder, arcuate valves controlling said ports slidable between said outer cylinder and said inner cylinder and sealing-ring, means to reciprocate said valves. means to hold said sealing-ring to its hearing on said inner cylinder, means to lubricate said valves and piston. one at least of each pair of contacting surfaces between said sealing-ring and valves having a channel lubricant in which tends to seal the joint between the surfaces against the escape of gas under pressure.

12. In an internal-combustion engine. the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder. a. second cylinder inside of and spaced inwardly away from said outer cylinder, a sealing-ring bearing endwise on said inner cylinder and having ports in substantial register with said cylinder ports. a piston reciprocatorv in said inner cylinder. arcuate valves controlling said ports slidable between said outer cylinder and said inner cylinder and sealing-ring. means to reciprocate said valves. means to hold said sealing-ring to its bearing u said inner cylinder, and means to lubriate said valves and piston, said sealing-ring 1 its outer surface in contact with said valves aving channels both above and below its orts lubricant in which tends to seal the )int between the surfaces against escape of as under pressure.

13. In an internal-combustion engine, the ombination of an outer. cylinder having inlet nd exhaust ports, a head for said cylinder,

second cylinder inside of and spaced inrardly away from said outer cylinder, a sealngring bearing endwise on said inner cylinler and having ports in substantial register vith said cylinder ports, a piston reciprocaory in said inner cylinder, arcuate valves ontrolling said ports slidable between said alter cylinder and said inner cylinder and ealing-ring, means to reciprocate said valves, means to lubricate said valves and piston, md a hold-down ring bearing on the upper 11d. of said sealing-ring, one at least of the :ontacting surfaces of said hold-down ring Lfld sealing-ring having a channel lubricant n which tends to seal the oint between the ;urfaces against the escape of gas under pres- ;ure. v

14. In an internal-combustion engine, the :ombination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, 1 second cylinder inside of and spaced i'nwardly away from said outer cylinder, a seallug-ring bearing endwise on said inner cylinder and having ports in substantial register with said cylinder ports, a piston reciprocatory in said inner cylinder, arcute valves controlling said ports slidable between said outer cylinder and said inner cylinder and sealing-ring, means to reciprocate said valves, means to lubricate said valves and piston, and a holddown ring bearing on the upper end of said sealing-ring, one at least of the contacting surfaces of said sealing-ring and inner cylinder and one at least of each pair of contacting surfaces of said sealing-ring and valves and one at least of the contacting surfaces of saidhold-down ring and said sealing-ring having a channel lubricant in which tends to seal the joint between the surfaces against the escape of gas under pressure.

15. In an internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, a second cylinder inside of and spaced inwardly away from said outer cylinder, a piston slidable in said inner cylinder, a sealingring bearing on an end of said inner cylinder and having ports in substantial register with said cylinder ports, arcuate valves controlling said ports and slidable between said outer cylinder and said inner cylinder and sealing-ring, means to reciprocate said valves, a hold-down ring bearing on said sealing-ring, and a flexible cover over the joint between, and adapted'to be flexed by the gas pressure in the cylinders outwardly against, said holddown ring and said sealing-ring.

16'. In an internal-combustion engine, the combination of an outer cylinder having inlet and exhaust ports, a head for said cylinder, a second cylinder inside of and'spaced inwardly away from said first cylinder, a piston slidable in said inner cylinder, a sealing-ring bearing on an end of said inner cylinder and having ports in substantial register with said cylinder ports, arcuate valves controlling said ports and slidable between said outer cylinder and said inner cylinder and sealing-ring, means to reciprocate said valves, and a flexible cover over the joint between, and adapted to be flexed by the gas pressure in the cylinders outwardly against, said inner cylinder and sealing-ring.

17 In an internal-combustion engine, the combination of a cylinder having port means, a head for said cylinder, a piston slidable in said cylinder, a connecting-rod joined to said piston, means controlling said port means, and means to seal the gas pressures in said cylinder including a flexible sealing member subjected to, and capable of flexing under, the gas pressure in said cylinder to confine such pressure therein against leakage between said head and cylinder.

18. In an internal-combustion engine, the combination of a cylinder having port means, a head for said cylinder, a piston slidable in said cylinder, a connecting-rod joined to said piston, means controlling said port means, and means to seal the gas pressures in said cylinder including a transversely-flexible sealing-ring subjected to, and capable of flexing under, the gas pressure in said cylinder to confine such pressure therein against leakage between said head and cylinder.

19. In an internal-combustion engine, the.

combination of an outer cylinder havingiinlet and exhaust ports, an inner cylinder 1nside of and spaced inwardly away from said outer cylinder, a pair of valves between and slidable lengthwise of said cylinders, means to reciprocate said valves, a head for said outer cylinder, a circumferentially expansible sealing-ring inside of and adapted to press outwardly against said valves and bearing endwise on said inner cylinder, said sealingring having an intake-port in substantial register with said outer cylinder inlet-port and a single unbridged exhaust-port in substantial register with said outer cylinder exhaust-port, means to prevent gas pressure leakage between said sealing-ring and said inner cylinder and between said sealingring and said cylinder-head while permitting circumferential expansion of said sealmgring against said valves, a piston reciprocatory in said inner cylinder, a shaft, and means operatively connecting said piston and shaft.

20. In an internal-combustion engine, the

combination of an outer cylinder having inlet and exhaust ports, an inner cylinder inside of, spaced inwardly away from, and having its upper end lower than said ports of said outer cylinder, a pair of valves between and slidable lengthwise of said cylinders, means to reciprocate said valves, a head for said outer cylinder, a circumferentially expansible sealing-ring inside of and adapted to press outwardly against said valves and hearing endwise on said inner cylinder, said sealing-ringhaving an intake-port in substantial register with said outer cylinder inlet-port and a single unbridged exhaustport insubstantial register with said outer cylinder exhaust-port, resilient means acting on said sealing-ring longitudinally to prevent gas pressure leakage between said sealing-ring and said inner cylinder and between said sealing-ring and said cylinder-head while permitting circumferential expansion of said sealing'ring against said valves, a piston reciprocatory in said inner cylinder, a shaft, and means operatively connecting said piston and shaft.

In witness whereof I have hereunto set my hand.

RALPH L. SKINNER.

aeaaiao 

